1. Background of the Invention
The present invention relates to antivenoms and processes for their preparation. More particularly, the invention relates to snake antivenoms and processes for their preparation.
2. Description of Related Art
A number of animals including snakes, gila monsters, spiders and bees produce venoms which are hazardous to man. For example, approximately one million people throughout the world are bitten each year by poisonous snakes. It has been estimated that of these some 100,000 die and that another 300,000 will suffer some form of disability for the remainder of their lives. This is probably a gross underestimation due to lack of detailed records from some parts of the world.
Snake venoms, produced primarily for the procurement of prey or in a defensive role, are complex biological mixtures of upwards of 50 components. Death of prey from a snake bite is due to respiratory or circulatory failure caused by various neurotoxins, cardiotoxins (also called cytotoxins), coagulation factors, and other substances acting alone or synergistically. Snake venoms also contain a number of enzymes which when injected into the prey start tissue digestion. The venoms thus contain substances designed to affect the vital processes such as nerve and muscle function, the action of the heart, circulation of the blood and the permeability of membranes. Most constituents of snake venoms are proteins, but low molecular weight compounds such as peptides, nucleotides and metal ions are also present (1).
Poisonous snakes may be divided into 4 main families,
the Colubridae, the Viperidae, the Hydrophidae and the Elapidae (2). The systematics of these snakes is described in Tables 1.1 and 1.2. Rattlesnakes which are particular to the American continent are members of a subfamily of venomous snakes from the Viperidae family known as Crotalinae, genera Crotalus or Sistrusus (rattlesnakes) Bothrops, Apkistrodon and Trimerisurus. The two rattlesnake genera may be broken down still further into species and sub species. These snakes are also called the xe2x80x98pit vipersxe2x80x99 due to the presence of facial sensory heat pits, however their most prominent feature is the rattle which when present distinguishes them from all other snakes.
Each species or subspecies occupies a distinct geographical location in the North or South America. The venom of each species of rattlesnake contains components which may be common to all rattlesnakes, common to only some smaller groups or may be specific to a single species or subspecies (3).
Antivenom is the serum or partially purified antibody fraction of serum from animals that have been rendered immune to venom toxicity as a result of a regimen of injections of increasing doses of snake venom.
The scientific study of antivenom began with the work of Henry Sewell (5) in 1887 and has progressed throughout the present century. Currently, a large number and diversity of monospecific and polyspecific antivenoms are produced around the world.